The present invention relates to an electronic flash appratus used as an artificial source of light for taking photographs, and more particularly an auxiliary electronic flash apparatus which may be used with a main electronic flash apparatus in order to prevent underexposure or to eliminate shadows caused when only the main electronic flash apparatus is used.
When a flash exposure is made with only one electronic flash apparatus, a shadow of a subject is caused on a wall when the subject is standing close to it, depending upon the angle of illumination. In order to eliminate this shadow, an auxiliary or additional electronic flash apparatus is used. Furthermore an auxiliary electronic flash apparatus is used in order to supplement the flash light emitted from the main electronic flash apparatus when the intensity of said light is not sufficient.
When one or more auxiliary electronic flash units are used in addition to a main electronic flash apparatus. The user must set the exposure value of the camera based upon his experience and sixth-sense depending upon photographic conditions, often resulting in underexposure or an overexposure. That is, an optimun exposure rarely obtained under such conditions.